Automatic rack un-loader and loader for plating machines



June 24, 1958 c. R. MERVYN ETAL 2,340,219

AUTOMATIC RACK UN-LOADER AND LOADER FOR PLATING MACHINES Filed April 30,1957 I 5 Sheets-Sheet 1 I 25 I INVENTORS. CHAR/.55 E. MEEVYM y RUDOLPHL/sTAz H 22% E. Kqosu HE E w/al A/JWM J a v ATTORNEY June 24, 1958 c. R.MERVYN ETAL 2,840,219

AUTOMATIC RACK UN-LOADER AND LOADER FOR PLATING MACHINES Filed April 50.1957 5 Sheets-Sheet 2 L IQ I NAwUm \L HE. E

M 5 M 4 T KN E 5 0 EM 0 W 6 A WELK E O mwmd CQH/M June 24, 1958 c. R.MERVYN EIAL 2,840,219

AUTOMATIC RACK UN-LOADER AND LOADER FOR PLATING MACHINES Filed April 30,195'! 5 Sheets-Sheet 3 flab THE. E 451 June 24, 1958 R. MERVYN arm.

AUTOMATIC RACK UN-LOADER AND LOADER FOR PLATING MACHINES Filed April 30,1957 5 Sheets-Sheet 4 FLE.Q

. I? 5 mm N T E 0 m m w VM 5 A A WZL J W 1 E L W a W 0% BY HA C. R.MERVYN EI'AL AUTOMATIC RACK UN-LOADER AND LOADER FOR PLATING MACHINESFiled April 30, 1957 June 24, 1958 5 Sheets-Sheet 5 3 I02 9 I 90vINVENTOR.

N E Y W WKN m ma w M 6 A A L E EMY awm M u @Qw/Wfl I Patented June 24,1958 AUTOMATIC RACK UN-LOADER AND LOADER FOR PLATING MACHINES Charles R.Mervyn, Mayfield Heights, Rudolph Listak, Wickliffe, and Harry E. Kaden,Cleveland Heights, Ohio, assignors to Newar't Manufacturing Company,Cleveland, Ohio, a corporation of Ohio Application April 30, 1957,Serial No. 656,140

3 Claims. c1. 198-20) This invention relates to automatic loadingdevices and particularly to a rack loader for continuous plating machineconveyors.

. Conducive to a better understanding of the invention, it may be wellto point out that in the electro-plating of small objects, such aselectric switch boxes; which are stamped from sheet steel and thereforerequire a corrosion resistant plating of zinc or cadmium metal; it iscustomary to carry out the plating process with'a socalled continuousplating machine.

Such a machine embodies a series of washing, plating, and rinsing bathswhich are arranged in a'closed circle. It is usual to have a circularconveyor system associated with the baths, which embodies a series ofpivoted arms which carry the objects to be plated and dips them,progressively, in the various baths required 'by the" plating process.The arms are carried past the various baths or tanks by an endlesschain, and the arms are made to dip and lift the objects to be plated,in and. out of the tanks, by meansof cams operable by a suitable timingdevice. The objectsv to be plated are placed -on the conveyor arms at aloading-point. The arms are then in dexed from tank to tank through theplatingprocess, and automatically returned to their starting point withthe objects completely processed.

In the case of small objects, such as electric switch boxes, it iseconomically impractical to plate them one at a time, and it istherefore customary to load them on a plating. rack accommodating 50 or60 boxes; the racks being suspended in pairs on the plating conveyorarms, which carry them from station to station through the platingcycle.

The plated switch boxes areunloadedmanually from the racks, and thentheracks must be lifted from the conveyor arm and reloaded with unplatedboxes; The loaded rack must then be lifted and re-placed on the conveyorarm. This requires considerable physical-effort on the part of theoperator, since the loading racks are very heavy. Furthermore, there isan inclination onthe part of the operator to load less than the maximumnumber of boxes on each rack in order to reduce the weight to be lifted.Again, the speedjof the manual rack loading operation, determines thespeed of the conveyor, since the conveyor cannot advance until theloaded rack is replaced on the conveyor arm. Bothlof these factors tendto reduce the operational efliciency of the plating machine. The primaryobject of this invention, therefore, is to provide an automatic rackloaderfor conveyor arms that will lift empty racks olf the conveyor arm,carry them to a manual loading position, and then return the loadedracks to the conveyorarm and replace them thereon.

Another object isto provide a device Whose operational stepsareRcontr'olle'd by a cyclic'mecha'nical and'elec trical' circuit,requiring no manual supervision and: acting entirely independently ofthe speedof the humanmanual b'oxloader; I Still another object is"to'provide' such a device that" is integrated with the movements oftheconveyo'r: arms;

. 2 so that it only moves when the conveyor arm is in its loadingposition.

A further object is to provide an automatic rack load er, of the typestated, that requires no physical effort on the part of the operatorother than that required to place the individual objects'to be plated onthe racks.

Another object is to provide such a device that is rugged in structureand reliable'in operation.

These and other objects of the invention'will become apparent from areading of the following specification and claims, together with theaccompanying drawings, wherein like parts are referred to and indicatedby like reference characters,'and wherein:

Figure 1 is a side elevation of the rack loading machine that is thesubject of this invention,showing it in its rack unloading position, atthe moment prior to the lifting of the racks off a conveyor arm;

Figure 2 is a side elevation of the same, showing it in an intermediateunloading position wherein'the racks have been lifted off the conveyorarm and aresuppo'rted on the bracket fingers of the loader;

Figure 3 is a side elevation of the unloader in its fully retractedmanual loading position, with the racks loaded with unplated boxes,andalso showing the bracket and supported loaded racks in an alternate,conveyor arm' engaging position, indicated in broken outline;

Figure 4 is a rear elevation of the carriage and track, showing thelocation of certain limit switches;

Figure 5 is a schematic layout of the pneumatic system;

Figure 6 is a top plan view of the device taken along the line and inthe direction of the arrows 6-=-6 of Figure 1; i

Figure 7 is a front elevation of one of the bell cranks;

Figure 8 is a right end view of the same; f

Figure 9 is a rear view of the carriage showing the vertical pneumaticcylinder in its retracted condition;

Figure 10 is a view of the same showing the'pneumatic cylinder in itsextended condition; I

Figure 11 is a schematic layout ofthe electrical 'control circuits;

Figure 12 is a front view of one of the racks;

Figure 13 is a schematic layout of the movements of the rack unloadingcycle; and

Figure 14is a schematic layout of the movements of the rack loadingcycle;

Referring more particularly to the drawings, there is seen the rackloader that is the subject of this invention, broadly-indicated by thereference numeral 20.

Reference numeral 21 indicates a base including a pair of spacedparallel rails, upon which a carriage 22' having wheels 23- is movablymounted. The rails, or track 21 extend from the loading station of theconveyor arm 44, outwardly therefrom, to the manual rack loadingposition-of the device.

The carriage has a pair of upright members 24' mounted thereon, and asecond-pair of shorter uprights 25 connected thereto, at the rearthereof, the uprights '25 are connected together through across-brace32, which provides a frame or base for supporting the upright pneumaticcylinder 29, described hereinafter.

A horizontal pneumatic cylinder 34 is mounted on an anchor plate 33 atthe forward end ofthe track 21, as shown in Figure 1,v with itspiston-rod 35 connected to the carriage 22 at the base of the uprightmember 24; The movement of the piston rod 35, in and out of thepneumatic cylinder 34 acts tomove the carriage 22 be- .tween first andsecond positions, longitudinally of the track 21 as describedhereinafter. Twopairofvertically spaced and horizontally aligned bearingblocks 26 are mounted on the front face of the uprights 24.

Four-triangularly shaped bell cranks 27 are mounted at their apices 45on short shafts journaled in the bearing boxes 26. The upper pair ofbell cranks 27, at apices 47, are connected to the lower pair of hellcranks, at their apices 47, through links 28, as seen most clearly inFigures 2, 3, 9 and 10. The upper pair of bell cranks are connected, atapices 47, through a cross bar 31. Thus all four bell cranks 27 willpivot simultaneously, on their apices 45, through the same are of travelupon movement of the cross-bar 31.

A pneumatic cylinder 29 is anchored on the crossbrace 32 connecting thetop of'the uprights 25. The piston rod 30 of the cylinder 29 isconnected to the bell crank cross-bar 31. Movement of the piston rod30in and outof the pneumatic cylinder 29, between first andsecondpositions, causes the four bell cranks 27 to simultaneously pivotbetween retracted and extended positions, respectively, on their bearingblocks 26, as described hereinafter. A bracket member 36 is pivotallymounted on the four bell cranks at their apices 46. The bracket 36 hastwo forwardly extending horizontal fingers 37. The fingers 37 arenotched at 48 to receive the racks 40, as described hereinafter.

The racks 40, as illustrated in Figure 12, are rectangular in shape andhave two mounting hooks 42 extending upwardly of them edge thereof.Reference numerals 41 indicatea plurality of pegs secured to the rackframe which function as supports for the switch boxes 43. It is ofcourse to be understood that any type or size article may be supportedon the racks 40, in which case the spacing and shape of the pegs 41 mayhave to be altered to suit the articles being plated. i

Referring to Figure there is seen the schematic layout of the pneumaticsystem. Reference numeral 39 indicates a compressed air line leadingfrom a source of compressed air, not shown. Reference characters A,

B and C, D indicate solenoid controlled air valves which control theflow of air to the two-pneumatic cylinders 34 and 39, respectively.Reference characters L1 and L-3 indicate limit switches which actuatesolenoids A and B, respectively. Reference characters L2 and L4 indicate,limit switches which actuate solenoids C and D respectively. p

The motions through which carriage 22 and bracket 36 go, upon activationof the various valves A, B, C and Dis as follows: I V

Activation of valve A causes the carriage 22 to be pulled forward towardthe conveyor arm 44. Activation of valve B causes the carriage 22 to bepushed away from con-.

veyor arm 44, and back to its original-position..

Activation of valve C causes piston-rod 30 of pneumatic cylinder 29 topush upward, thereby pivoting bellcranks 27 forward, and carrying theattached brackets 36 upward and forward in a circular counter-clockwisearc, to the position illustrated in Figure l.

Activation of valve D causes the piston-rod 30 to be pulled downwardinto cylinder 29, thereby pivoting the bell cranks 27 backward to theiroriginal positions, and carrying the bracket 36 upward and backward inaclockwise arc, to the position illustrated in Figure 3, in full line. Astudy of Figure 1 of the drawings will reveal that the racks 40 aresuspended from the conveyor arm 44 by means of forwardly curved books42. In order to remove the racks 40 from the conveyor arm 44 it isnecessary to slide the bracket fingers, 37 through the rack frames andthen lift the racks upwardly in a vertical arcu-,

ate clockwise path in .order to un-hook the racks from the conveyor arm44, as illustrated in Figure 2. 7 Once they are unhooked it is necessaryto lower them so-that they will pass under the conveyor arm. and thenthey are moved horizontally away from the conveyor: arm to the manual[box loading position, as illustrated in Figure 3, p

Figure 11 is'aschematic layout of the electricalcycling circuits whicheffect these various movements automaticah 1y. It will be s eenlthattheelectrical control circuits of the loader 20 and the "conveyoroperational motors I and J are integrated so that none of them willfunction in a conflicting manner. The motor I controls the lifting andlowering action of the conveyor arm 44, while the motor I controls thelateral transfer or indexing motion of the plater conveyor arms 44, asexplained hereinbefore.

In the following explanation of the operation of the device through itsunloading and loading cycle, the following meaning of the terms closedand open is indicated with reference to Figure 11. 7

Limit switch L-l, closed means terminals 101 and 102 are contacted bybatopen means terminals 103 and 104 are contacted by bar 100.

Limit switchL-2, closed means terminals 201 and 202 are contacted by bar200; open means terminals 203 and 204 are contacted by bar 200.

Limit switch L3, closed means terminals 301 and 302 are contacted by bar300; openmeans terminals 303 and 304 are contacted by bar 300. Limitswitch L4, closed means terminals 401 and 402 are contacted by bar"400;open'means terminals 403 and 404 are contactedby bar 400.

Limit switch L7, closed means bar 700 is contacting terminal 702; openmeans bar 700 iscontacting terminal 701.

Limit switch L-8, open means bar 800 is contacting terminal 802; closedmeans bar 800 is contacting terminal 801.

Limit switch L-9, closed'means bar 900 is contacting terminal 901; openmeans bar 900 is contacting terminal 902. a

The limit switches LA and L3 are mechanically tripped by the to and fromovement of the carriage 22. The limit switches L-2 and L-4 aremechanically tripped by a circular cam 38 mounted on oneof'the bellcranks 27at its pivot shaft.

The limit switches L7 and L-8 are located to the rear of the track 21,as shown in Figure4, and are tripped by contact with the moving carriage22. p

I The limit switch L-,9 is located at the front end of the track 22 andis tripped by contact with the carriage 22.

This mechanism performs two basic operations-first, unloading manuallyemptied plating racks from. the plater conveyor arms, and, second,loading manually loaded plating racks on to the conveyor arms. These twobasic operations constitute two separate basiccycles, which arehereinafter referred to as loading and unloading cycles. Each of the twobasic cycles comprise three separate motions which are graphicallyillustrated in Figures 13 and 14. Figure 13 illustrates the unloadingcycle, while Figure 14 illustrates the loading cycle.

At the start of the unloading cycle the carriage is back at point W ofFigure 13, with the bi'acket'36 in its extended position as illustratedin Figure 1. At point W the condition of the various limit switchesillustrated in Figure 11 is as follows:

L-l is closed L-2 is open L-3 is open L-4 is closed L7 is closed L-8 isopen L9 is closed It is to be understood that under these conditions andwith the conveyor arm indexed to its unloading position in front oftrack 21, the plating machine timer-control willj energize the loadercircuit. Following this activation solenoid valve A is energized,causing the carriage 22 to move frornapoint W to. point V throughhorizontal motion Z. At this point the bracket fingers 37 will be thrustthrough theracks 40 which are still suspended from the conveyor arm 44,as illustrated in Figure 1. i T

t'rippedopen Following the schematic layout of Figure 11, it is seenthat solenoid valve Dis actuated. This-causes the pistonrod 30 to bepulleddown into-cylinder29"; thereby pivoting the bell cranks 27r'earwardly. The bracket fingers 37 are moved'from point V topoint'Uthrough an arcuate clockwise path Y. This lifts the rackhooks 42 up andoff the conveyor arm 44, as illustrated in Figure 2;

The racks 40 are now seated across the fingers 37 in notches 48, whichhold themin position on the fingers 37. At point U the tops of the rackhooks 42 are belowthe arm, so that the forward hook may pass under thearm 44 during the next movement;

At point U:

L-1 is open L-2 is mechanically'tripped closed" L-3 is closed 1 L-4 ismechanically tripped open L-7 is closed- L-8 is open L-9 is openFollowing the schemati'c'layout of Figure 11 it is now seen thatsolenoid valve B is activated, causing the carriage 22 to travel frompoint U to manual loading station T, through horizontal motion X. Theracks 4t) suspended on the fingers 37 are now at the manual loadingstation, as illustrated in full outline in Figure 3. The unloading cyclehas now been completed. After a time interval controlled by the timer ofthe plating machine, the loading cycle is initiated.

The loading cycle motions are illustrated schematically in Figure 14,wherein point T of Figure 13 becomes point T of Figure 14.

At point T:

L-l is mechanically tripped closed L-2 is closed L-3 is mechanicallytripped open L-4 is open L-7 is mechanically tripped open L-8 ismechanically tripped closed L-9 is open Following the schematic layoutof Figure 11 it is seen that solenoid valve A is activated, causing thecarriage to move from point T to U through horizontal motion X.

At point U:

L-l is mechanically tripped open L-2 is closed L-3 is mechanicallytripped closed L-4 is open L-7 is open L-8 is closed L-9 is mechanicallytripped closed Following the schematic layout of Figure 11 it is seenthat solenoid valve C is activated causing the piston-rod 30 of cylinder29 to be pushed upward, thereby pivoting the bell cranks 27 forward in acounter-clockwise motion. The bracket fingers 37 move from point U topoint V' through counter-clockwise arcuate path Y, thus rte-hooking theracks 40 on to the conveyor arm 44, as indicated in dotted outline inFigure 3.

9 1 Q m r r, 6 Atp'oint V:

- L-l is. open I L-2'is mechanically tripped open L3 is closed 1 L4 ismechanically tripped closed L-7- is open L8 is closed "L-9 is closedFollowing the schematic layout of Figure l1, it is seen that solenoidvalve B is actuated. The carriage 22 is now moved back from pointrV' topoint W through horizontal motion Z. ,Thus the rackslti are'leftsuspended on the conveyor arm 44, which is ready to the first positionof the plating process;

At point W: V L-l is mechanically tripped closed L-2 is open L 3ismechanically tripped open L-4 is closed L-7 is mechanically trippedclosed L-S is mechanically tripped open L9 is closed The rack loader 20is nowback at its original position, clear of the conveyor arm 44, freeof racks 40 and ready for another unloading cycle, starting at point Wof Figure 13;

The next unloading cycle, however, cannot start until the next conveyorarm, carrying empty racks, has indexed into its unloadingposition,.since'the plater circuits control the initial activation ofthe loader circuits, as seen in Figure 11. 7

Note thatlimit switches L-2 and L-4 work on cam 38. One will always beclosed when the other is open. Similarly switches L1 and L-S; and L-7and L8 will always be paired alternately open and closed. Limit switchL-9 will trip only when L-l and L-3 are tripped.

The rack loader just described will function to automatically unload andload racks as long as the plating machine is in operation, withoutrequiring any physical or mental action on the part of the operator.

It will now be clear that there has been provided a device whichaccomplishes the objectives heretofore set forth. While the inventionhas been disclosed in its preferred, form, it is to be understood thatthe specific embodiment thereof as described and illustrated herein isnot to be considered in a limited sense'as there may be other forms ormodifications of the invention which should also be construed to comewithin the scope of the appended claims.

We claim:

1. In combination with a conveyor of the type having the conveyor armsbeing cyclically indexed past a loading position when the racks areempty; a rack loader, comprising, a base member including a trackaligned at one end with the aforesaid conveyor loading position andextending away therefrom to a work leading position; a carriage membermounted on said track and movable longitudinally thereof between saidconveyor loading and work loading positions; a bell crank pivotallymounted on the carriage and movable between a first and a secondposition; a bracket member mounted on the bell crank and movable therebythrough a vertical arcuate path relative to said carriage between afirst extended position and a second retracted position; the brackethaving two, spaced, parallel and forwardly extending fingers; means formoving said carriage toward the conveyor arm when the arm'is in itsloading position and the bracket in its first, extended position,wherein the bracket fingers are aligned with the empty racks suspendedon the conveyor arm; means for pivoting the bell crank to its secondposition whereby the bracket member is moved to its second,

retracted, position, wherein the racks are lifted from the Conveyor armby the fingers and supported thereby; means 7 for moving the carriageand supported racksflongitudi; nally of the track to the work loadingposition; means for returning the carriage: and loaded racks along thef'track to the conveyor arm; means for pivoting thebell crank andbracket .to their firstypositions, wherein thebracket fingers arealigned with the conveyor arm and} the racks supported on the fingersare replacedton the conveyor arm; and means for moving thecarriagellongitudinally of the track, clear of the conveyor loadingposition.

2. A device of the type defined in claim number 1 and furthercharacterized by the means, for movingthe carriage longitudinally of thetrack being a first pneumatic cylinder andthe means .for pivotingthejbell crank between its first and second position being a secondpneumatic cylinder. 7 i

3. In combination with a conveyor of the type having a plurality of armsforsuspending work" holding racks;

the conveyor arms being cyclically indexed past a loading position whenthe racks are empty; a rack loader, comprising, a base member includinga traclt' aligned at one end with the aforesaid conveyor loadingposition and extending away therefrom to'a work loading position; acarriage member mounted on the track and movable longitudinally :thereof between a first position, at the conveyor arm, and asecondposition, atthe work loading end of the track; a first pneumaticcylinder mounted on the base, having its pistonrod connected to thecarriage, the piston rod being movable between first and secondpositions, the carriage being in its first position when the piston rodis initstfirst position and in its second position when the piston rodis in its second position; the carriage having a pair of spaced uprightmembers mounted thereon; a pair of vertically spaced bearing blocksmounted on each of the upright members, each of said paired bear- 8 ingblocks being horizontally aligned with its opposite bearing block on thepppos ite upright;,member; a bell crank pivotally journaled in each ofsaid hearing blocks, the bell cranks on; theiupper bearingfblo'cks beingjoined through links to those on the lower bearinggblocks; a bracketmember mounted on the several bell cranks and movable in a verticalarcuate path between first and second positions, forwardly andrearwardlyfof ;SaidI carriage uprights, upon the pivoting of the bellcranks between a first and; second position, the said bracket hayingapair of forwardly extending rack engaging fingers mounted thereon Q asecondpneumaticcylinder mounted on the carriage, to the rear of saidupright member having its piston rod connected to the upper bell cranks,the piston rod being movable between first and secondt positions wherein'the bell cranks, and attached bracket member are moved between; theirfirst and second positions respectively, each of said pneumaticcylinders having elec- .trically operated valve; means and controlcircuits therefore, operable to energize the cylinders to cause thepistons thereof to move between their first and second posi-, tions in apredetermined sequence; and an electric cycling circuit controlled bythe position of the conveyor arm and acting to initiate the loadingcycle when the conveyor arm moves into its loading position.

References Cited in the file of this patent UNITED STATES PATENTS V2,103,901 Gordon Dec. 28,1937 2,779,490 Clarke Jan. 29, 1957 2,806,577Lang Sept. 17, 1957 Hauck Sept. 24, 1951

